Methods of entrapping enzymes in chitosan matrices using mild conditions, such as methods that are compatible with the entrapment of acid-sensitive and/or heat sensitive enzymes, are described. The methods can provide biocatalytic materials with high chitosan to enzyme mass ratios where one or more enzymes can remain active and stably entrapped in the chitosan matrix for many months and/or after repeated washings. Also described are materials including a solid chitosan matrix having at least one enzyme stably entrapped therein, including fabrics, textiles and other flexible materials at least partially coated with one or more layer of the solid chitosan matrix having at least one enzyme stably entrapped therein and the use of the materials as biocatalyst systems, for example in biogas upgrading and other applications.
